Omni-node: TODOs

[serban300]

Opening this issue in order to track all the todos that we uncover related to omni-node and that we can't address on the spot.

1. Metadata checks:

• if possible we should check if the runtime has all the RuntimeApis that are required. For example the basic ones
• also would be nice to check if the RPCs that are exposed are supported by the runtime. See this comment: polkadot-parachain simplifications and deduplications #4916 (comment)

2. Remove the benchmark commands from polkadot-parachain: see comments 1, 2, 3: Here we need to wait for the CI bot bench commands to be migrated to omni-node first:

• CI short benchmarking with frame-omni-bencher  #4405
• Short benchmarking in CI with frame-omni-bencher + extract chain-spec-builder stuff to get_preset polkadot-fellows/runtimes#379

[kianenigma]

Closing in favor of #5564 and #5565